Senior ministers have rallied round beleaguered Culture Secretary Tessa Jowell as questions continued to mount about her involvement in her husband's financial affairs.

Allies of Ms Jowell appealed for a line to be drawn under the whole issue after the shock announcement that she and David Mills were to separate after 27 years of marriage.

But Tory MPs warned that they would continue to press for answers over whether she broke ministerial and parliamentary rules by failing to declare properly details of her husband's controversial financial dealings.

And many Labour MPs still have a deep sense of unease about the world of secretive payments through complex networks of offshore companies which the affair has exposed.

Cabinet ministers David Miliband and Hilary Benn both insisted Ms Jowell was secure in her job and would not be forced out by the continuing media revelations.

"I think Tessa is a very, very honest woman and I have a lot of confidence in her and so do her colleagues," said Mr Benn.

"I think it's really important that she is allowed to get on with her job and that's why so many people are supporting her despite the difficulties she has found herself in."

Mr Miliband said that her position should not be affected by allegations in Italy that Mr Mills received a £350,000 bribe from Prime Minister Silvio Berlusconi over evidence he gave in a court case against him.

"She shouldn't be charged with guilt by association. She has got a job to do and as long as she is doing it to a high standard I think she should carry on with it," he said.

He dismissed as "grotesque" suggestions that Alastair Campbell was behind the announcement that the couple were separating in order to save Ms Jowell's career.

However, there was little visible support for Ms Jowell among the Cabinet's "big hitters", with Mr Blair conspicuously ignoring questions on the subject when he gave a speech to trade unionists in London.

The latest questions concern a report by The Observer that Mr Mills made a £67,000 profit on shares he bought in the Old Monk Company pub chain in 1998 at a time when Ms Jowell was a public health minister.

Aides insisted that all the issues concerning her duty of disclosure under the Ministerial Code had been fully dealt with in statements last week by Mr Blair and Cabinet Secretary, Sir Gus O'Donnell.

However, Tory MP Nigel Evans, a member of the Commons Culture, Media and Sport Committee, said he would be writing to Ms Jowell this week over whether she had properly declared all her and her husband's interests.

He warned that he was prepared to refer her to the Commons Standards and Privileges Committee if he failed to get a satisfactory response.

"Clearly we are sensitive to the Secretary of State's personal circumstances but the latest revelations add fuel to the fire surrounding this issue," he said.

"The Secretary of State must answer questions relating to the latest allegations, as well as addressing the questions which remain outstanding from last week."

A grim-faced Ms Jowell returned to her London home this afternoon having spent much of the weekend lying low at a country cottage of the Lord Chancellor, Lord Falconer of Thoroton, in Nottinghamshire.

Labour peer Baroness Jay, a close friend of both Ms Jowell and Mr Mills, said that they were both "very, very miserable" about the separation.

"She is obviously very sad and deeply upset about the break-up of her marriage," she said.

"I think it's a devastating blow to them that the pressures they have both felt under have meant that they just feel now they must give each other some space - both the emotional kind of space and physical space - to try to resolve these problems separately."

The final straw for Ms Jowell was said to have been the disclosure that Mr Mills had dragged Mr Blair's name into the affair in a letter to the Dubai authorities claiming he had the support of public figures "from the Prime Minister down".

Ms Jowell is due to return to the Commons today to face Culture, Media and Sport questions, although it is by no means clear that opposition MPs will be able to ask her about her financial affairs.

Instead Labour loyalists may take the opportunity to stage a show of support in the Commons chamber.